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            <h2 class="title" style="clear: both"><a id="ReplacingEntryWCursor"></a>Replacing Records Using Cursors</h2>
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      <p>
        You replace the data for a database record by using
        

        

        <span>
            <code class="methodname">DBC-&gt;put()</code>
            
            with the <code class="literal">DB_CURRENT</code> flag.
        </span>
            
    </p>
      <a id="c_cursor9"></a>
      <pre class="programlisting">#include &lt;db.h&gt;
#include &lt;string.h&gt;

...

DB *dbp;
DBC *cursorp;
DBT key, data;
char *key1str = "My first string";
char *replacement_data = "replace me";
int ret;

/* Initialize our DBTs. */
memset(&amp;key, 0, sizeof(DBT));
memset(&amp;data, 0, sizeof(DBT));

/* Set up our DBTs */
key.data = key1str;
key.size = strlen(key1str) + 1;

/* Database open omitted */

/* Get the cursor */
dbp-&gt;cursor(dbp, NULL, &amp;cursorp, 0);

/* Position the cursor */
ret = cursorp-&gt;get(cursorp, &amp;key, &amp;data, DB_SET);
if (ret == 0) {
    data.data = replacement_data;
    data.size = strlen(replacement_data) + 1;
    cursorp-&gt;put(cursorp, &amp;key, &amp;data, DB_CURRENT);
}

/* Cursors must be closed */
if (cursorp != NULL) 
    cursorp-&gt;close(cursorp); 

if (dbp != NULL)
    dbp-&gt;close(dbp, 0);</pre>
      <p>
        Note that you cannot change a record's key using this method; the key
        parameter is always ignored when you replace a record.
    </p>
      <p>
        When replacing the data portion of a record, if you are replacing a
        record that is a member of a sorted duplicates set, then the replacement
        will be successful only if the new record sorts identically to the old
        record. This means that if you are replacing a record that is a member
        of a sorted duplicates set, and if you are using the default
        lexicographic sort, then the replacement will fail due to violating the
        sort order. However, if you
        provide a custom sort routine that, for example, sorts based on just a
        few bytes out of the data item, then potentially you can perform
        a direct replacement and still not violate the restrictions described
        here.
    </p>
      <p>
            <span>Under these circumstances, if</span>
            
        you want to replace the data contained by a duplicate record, 
            <span>
                and you are not using a custom sort routine, then
            </span>
        delete the record and create a new record with the desired key and data.
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